Building a pressure washer ~30l/min 4000psi - DIY

[wutsdat]

Hi again guys,

so my last post was about finding a supplier in Europe for a 25-30l/min 4000psi pressure washer with a name brand engine and a pump- didnt have any luck with that.

Long story short, did some research and decided ill man up and build my own ( IM IN NO RUSH ) motor is already ordered- will start building when comes spring. Dont have any spare time before that and dont want to half-ass this, just enough time for me to collect all the peaces and knowledge.

skid:

I will fabricate this myself, few psc of metal and 2 wheels.

motor : 

Honda GX690 TXF4 Engine    22.5hp   6.7 L/hr - 3 600 rpm

Pulley:
For pump option A: pump pulley:  8.4″  - engine pulley: 3.4″

For pump option B: pump pulley:  7.4″  - engine pulley: 3.6″

pump: 

A) AR model RTX30                23.9hp    30l/min -     4350 psi    1450RPM     - INDUSTRIAL

B) AR model XWAM7G40N    19.2hp    25.5l/min -  4000 psi    1750RPM     - COMMERCIAL 

Idle Down Controls: ( for when i release the trigger the engine will idle )

Still looking for a good supplier - any suggestions ?

And ofcourse all suggestions are welcome since most of you are smarter than me anyway ?

 

[#cleanwindows]

https://www.dualpumps.co.uk/groups/THOR__Thor_Series_Pressure_Washers

There you go.

I bought one for a second van a few years ago, probably the best pressure washer I've used - except the one in my current van, which has the same spec as the 41LPM machine but also built in fuel tank (that'll run for seven days).

https://icmuk.co.uk/products/icm-contractor-41-l-min-210-bar-twin-lance/

Downside of the ICM - it's a forklift truck job every time I want it servicing - 300 kilos. (Amended - Mine I now see is the 48LPM model)

Dual Pumps 41LPM is only 200 kilos.

If you go down the build your own route the Anno Reverbi pump (AR) are a great pump.

 

[Dave B]

When you go that big it needs to be mounted on a skid and not removed from the van .

I got a 21lpm gx390 that doesn't come out the van.

To be honest there is nothing with a service or part change you can't do in 10 minutes yourself so no need to ever remove it.

Just bought new ignition coil for mine which will take5 minutes to change and space it correctly  .

You want to convert the unloader valve pipe to return to the tank when you release the trigger and never have to worry about overheating etc.

Ar are good pumps but mine is an interpump which is great also.

 

[#cleanwindows]

I need to satisfy high profile clients with a service record that comes from a company other than me. Started work at a store on Sunday evening and was asked for exactly that. That they got.

 

[wutsdat]

If i go with 25l/min i dont need the tank at all 95% cases up here, the water/pressure comes straight from personal or city pump and is enough. So makes sence to add Idle down control.
Yes, im thinking of truck mount with the ability to move if needed. How long hoses are you using ?

Since i already bought the engine i will go with that, bacause i have time and i will save tons im sure.

But mainly, i get exactly what i need. Though this is pretty nice.


With a 30 Hp, twin cylinder, Deutz diesel engine, driving a pump producing between 200 and 500 bar, with a range of flows between 20 and 48 L/minute, the ICM-CONTRACTOR is designed and built for constant use with the minimum of maintenance.


And yes, they are really heavy + i cant even imagine how much they ask for them. over 10k ?

 

[wutsdat]

and got 1 of my questions answered.


The Math of Pulley Sizing


There are complicated formulas for determining pulley ratios but in generic, layman terms, simply divide the driven component (pump) by RPM, the driver component (motor or engine) rated by RPM to get the required ratio.  In the example below, the pump RPM is 1070, for full output, while the motor is 1750 RPM.

Therefore, the ratio of the required pulleys would be 1070 (pump RPM) divided by 1750 (motor RPM) = .611

This means the pulley ratio must be .611 to drive the pump correctly.  Hypothetically speaking, if we had a 4 inch pulley on the motor, we would require a 6.55” pulley on the pump.  That mathematical equation is as follows: 4” divided by .611 = 6.55”

For the same pump, driven by a gas engine, 1070 (pump RPM) divided by 3400 (engine RPM) = .315

If the drive pulley on the engine is 4 inches in diameter, we need to calculate 4/.315 = 12.70.  This means that the pump pulley must be 12.70 inches, in diameter, to run the pump at 1070 rpm.  You can view a technical page from our catalog here – it will help to further explain the calculation process.

And ofcourse we can just use metric system.

 

[Baldmonkey]

Is that to blast a hole in space time ????

 

[Dave B]

I have 2 50m garden hose reels and 100m pressure washer hose. 

Never need to move it.

I did a job recently where I had to use the buffer tank as the flow was so bad.

Nowadays I always use the tank.

 

[wutsdat]

I have 2 50m garden hose reels and 100m pressure washer hose. 

Never need to move it.

I did a job recently where I had to use the buffer tank as the flow was so bad.

Nowadays I always use the tank.

How big of a tank are you using? Id imagine id use something around 150-200l 

Car is small and that should be enough IF the pressure is on the low side

 

[#cleanwindows]

The only machine I bought brand new was the Dual Pumps one.

The ICM Contractor would be around £10 000 but I never paid anywhere near that for it.

There are some cracking deals to be had if you look carefully.

I can see that you have gone down the DIY route but some of the larger drain jetters would have given you what you needed & there are always secondhand deals on Ebay.

Wutsdat - You say your car is small and a 200 litre tank should be enough, are you towing the set up, working out of your car or something else?

 

[wutsdat]

The only machine I bought brand new was the Dual Pumps one.

The ICM Contractor would be around £10 000 but I never paid anywhere near that for it.

There are some cracking deals to be had if you look carefully.

I can see that you have gone down the DIY route but some of the larger drain jetters would have given you what you needed & there are always secondhand deals on Ebay.

Wutsdat - You say your car is small and a 200 litre tank should be enough, are you towing the set up, working out of your car or something else?

Its a WV caddy, so there just isnt enough room for bigger one nor do i need one, as i explained, here we/home owners have good water pressure for 25-30l/min but to be on the safe side i am now thinking that something around 200l barrel would do the trick.

Sealed lid, since the barrel would sit in the car and if full, wont spill any water.

This idea any good ?

 

[#cleanwindows]

And a float valve to stop overfilling.

For years I've had a 1300 litre tank. Started this year with a 350 litre tank.

All you need is a tank big enough to give a buffer between the water filling up & the water being drawn from the tank.

200 litres in my changed perspective is  more than enough.

 

[#cleanwindows]

To add to that - it only works if you have a constant supply.

That's where the supply hose comes in.

If you're pulling up outside a residential customers you need to run the hoses across the pavement outside, you'll probably put down a sign or a couple of cones to warn of the trip hazards.

Try taking water to a point on an open supermarket car park, from a point on the front or rear of the premises, then take it across a carpark, where it will be driven over constantly, cones, signs, hose conduits all have to be part of the carried items. 

200 metres of 3/4 inch always carried and a further 100 metres of 1/2 inch can be thrown in when needed.

For commercial works hydrants are the preferred option.